Louis van Gaal has begun his time in charge of Manchester United by playing a 3-4-1-2 formation, an alignment with which he enjoyed success as Netherlands manager at the World Cup.

"Success" must be qualified, of course -- the Netherlands came third. However, it was a dramatically better performance than was expected, as many tipped them to finish behind Chile and Spain in the group stage. In the end, only a defeat to Argentina on penalties denied them a second consecutive appearance in the final.

However, it's worth remembering that 3-4-1-2 was Van Gaal's default formation, rather than his only one. He also played 4-3-3, 4-3-1-2, 3-4-3 and 4-2-3-1 at various stages, varying his approach according to the nature of the opposition, and the situation of the game. Besides, Van Gaal has never been a "template" manager, someone who brings an identical approach to different sides. He's often used 4-3-3 and 4-2-3-1 as his first-choice formations.

The question then, is simple. Why is he so keen to play a 3-4-1-2 at Manchester United?

The latter part of the formation makes most sense. In Wayne Rooney, Robin van Persie and Juan Mata, Van Gaal possesses three ultra-talented attackers who prefer to play centrally. None of the trio have been at their best for the past year -- in keeping with the rest of the United squad -- but all three are superbly efficient footballers.

Rooney, for all his faults, is just one goal behind third-placed Thierry Henry on the Premier League's all-time scoring list, Van Persie has finished as the league's top goal scorer in two of the past three seasons and Mata was close to being the best player in the league in his final complete season at Chelsea, racking up 12 goals and as many assists.

Using those three together in central positions makes perfect sense, which means a "...1-2" format is natural. In theory, the 3-4-1-2 allows United to have a spare man in defence and ensures plenty of thrust in wide positions.

Louis van Gaal, a renowned tactician, may have to realign Manchester United again, now that Angel Di Maria's transfer is complete.

It's highly questionable, however, whether the other seven outfield players suit the formation. For the first two games of the Premier League season, Van Gaal has been without any recognised full-backs, and therefore playing a four-man defence would have been extremely difficult, which is why using Antonio Valencia and Ashley Young as wing-backs was a logical, if far from perfect, solution. But when Rafael and Luke Shaw return to full fitness, and now that Angel Di Maria has completed his transfer from Real Madrid, it makes sense for Van Gaal to play 4-3-1-2, rather than 3-4-1-2.

Up front, Van Persie, Rooney and Mata would continue in a tight, central triangle, and while there would be less natural width (with the wing-backs becoming full-backs) there would be more forward running from the "shuttlers" on the outside of the diamond, who could charge forward with a solid holding midfielder protecting the defence.

The role of the shuttler involves great energy. Essentially, it means playing as a central midfielder but then providing width having made sudden diagonal bursts. In this particular position, Di Maria is arguably the world's best and it was particularly useful when he played in the same Real Madrid side as Cristiano Ronaldo, who always made the reverse movement, cutting inside from a wide starting position.

The Argentine is frequently misunderstood and often termed a winger, which suggests he's in the mould of Arjen Robben or Gareth Bale. In reality, at no point in his seven-year European career has Di Maria played in a front three -- he has generally been tucked inside into a deeper, more central position. At Benfica, for example, he excelled on the opposite side of the diamond to Ramires.

For Real Madrid under Jose Mourinho, he played a disciplined, narrow wide role in a 4-2-3-1 to compensate for Ronaldo and Mesut Ozil's attacking positioning; again, almost tucked back into a midfield three alongside Xabi Alonso and Sami Khedira. He turns defence into attack, rather than being stationed permanently in attack.

Meanwhile, for Argentina he's been fielded on the left of a midfield three under both Diego Maradona and Alejandro Sabella, although he was pushed wider in a 4-4-1-1 at the recent World Cup.

Di Maria offers flexibility to a United side whose opening two performances have been underwhelming.

Fitting Di Maria into a 3-4-1-2 would be more awkward because he doesn't belong in the front three, using him and Ander Herrera together in a two-man midfield would be risky and playing him as a wing-back would be a waste.

This 4-3-1-2 formation also would perfectly suit Herrera, another expensive United newcomer. He is a good all-round midfielder, almost a throwback as a box-to-box player, and accustomed to covering huge distances under former coach Marcelo Bielsa at Athletic Bilbao.

This system would release him to play his natural game, storming forward into attack and running in advance of Mata and Rooney, something obviously lacking in United's first two games of the campaign.

Further back, United could revert to a back four comfortably. Shaw and Rafael could be wing-backs, but they've both been trained as full-backs and would be more at home in those roles. Centrally, United's lack of defenders is less worrying if Van Gaal needs to play only two of them.

Perhaps the most interesting position would be the holding midfield role. Here, Van Gaal could play Michael Carrick or perhaps Phil Jones, who has been one of United's better performers in the opening two matches.

Carrick's distribution is superior but Jones would be capable of dropping back between the centre-backs, which would mean United could become a 3-4-1-2 as an option within matches, rather than as a default system. This would be useful against sides playing two strikers. The problem with the 3-4-1-2, as was shown against both Swansea and Sunderland, is that three-against-one at the back was entirely unnecessary, and left them overrun in other positions.

There are merits to every system, of course, and given that he spent the past couple of months drilling players in the 3-4-1-2, it seems that Van Gaal perhaps wanted to bring tried-and-tested training ground drills with him.

Nevertheless, the 3-4-1-2 requires specialist players in specialist positions, and this transfer window has not yet prompted the revolution in the playing staff Van Gaal was anticipating.

It's difficult to identify a key Manchester United player who loses out by Van Gaal playing 4-3-1-2 rather than 3-4-1-2. Ashley Young and Antonio Valencia wouldn't command a place, but then that's a reflection of their underperformance for the past two years anyway.

Van Gaal is a famously stubborn individual and would be reluctant to change his approach so soon, but Di Maria's arrival means United have a squad perfectly suited to 4-3-1-2.